Siemens JL63B300 – 300A 3 Pole Molded Case Circuit Breaker Order Now

The JL63B300 is a 3-pole, 300A molded case circuit breaker designed for commercial power distribution. As a legacy J-Frame unit, it provides robust thermal-magnetic trip functions with adjustable magnetic settings. This bolt-on breaker fits into Siemens P2, P3, P4, and P5 panelboards, as well as older ITE enclosures. It serves as a replacement for aging infrastructure and is superseded by the JD63B300. Rated for 65kAIC at 240VAC, it ensures reliable fault interruption and is HACR rated.